This invention relates to computer graphics generally and particularly to systems with morphing capabilities between two N-dimensional objects.
U.S. patent application xe2x80x9cMethod for Progressively Constructing Morphsxe2x80x9d, Sanjeev N. Trika, application Ser. No. 09/057,787, Apr. 8, 1998.
Metamorphosis, or morphing, describes a process to change one object to another. A morph between two objects A and B is a time-varying object C(time), where object C(initial time) equals object A and object C(finished time) equals object B. As the time value for object C(time) increases from the initial time to the finished time, object C(time) will likely present the illusion that object A xe2x80x9cmorphsxe2x80x9d into object B. Morphing between two or more objects over time is often a useful technique in education, entertainment and computer animation fields. Some example objects utilizing this morphing technique: an image, a polygon, a three-dimensional mesh or even an audio tone may all be morphed to another.
A typical morphing scheme between two images is that of optical cross-dissolving. In particular, this scheme fades out the original image while fading in the destination image. A user refines the resulting visual effect by specifying corresponding points between the two images. Such a morphing scheme requires much skill and tedious work to generate a visually appealing outcome.
Similar morphing approaches involving two polygons or two meshes have also been proposed. One such approach is disclosed in xe2x80x9cShape Transformation for Polyhedral Objectsxe2x80x9d, by James R. Kent, et al., Computer Graphics, Vol. 26, No. 2, July, 1992 (herein as Kent, et al.). The approach describes a process which generates two new three5 dimensional (3-D) polyhedral models that have the same or similar shape as their input counterparts. At the same time, the process calculates the transformation from one newly generated model to another. However, this process not only assumes the morphing of a particular type of objects, but is also computationally intensive.
Another approach is discussed in xe2x80x9cFeature-based Surface Decomposition for Correspondence and Morphing between Polyhedraxe2x80x9d, by Arthur Gregory, et al. (herein as Gregory, et al.) The method creates a morph between two 3-D objects based on a user""s selected vertices between the two objects. Since this method maintains the combined topologies of the original objects, the method requires much calculation and particular vertex selection.
All the mentioned approaches possess at least one of the following drawbacks: 1) these schemes often require tedious user-interaction to specify the corresponding points between the two objects. 2) Because of the difficulty in establishing a desirable vertex correspondence between the two objects, these techniques frequently only operate on objects with particular geometric properties. 3) These approaches often require tremendous amount of computation cycles and thus are time consuming.
As has been demonstrated, an improved method and apparatus is needed to morph two objects speedily without having to unnecessarily place algorithmic constraints on the objects.
A method and apparatus for morphing between two objects is disclosed. In one embodiment, a first object and a second object are subdivided into pieces wherein the objects contain an equal number of pieces. With the generated pieces, a mapping between the first object""s pieces and the second object""s pieces is created. A morph sequence is then generated based on the mapping, vertices of the first object""s pieces and corresponding vertices of the second object""s pieces.